In the field of motor vehicle technology, in hydraulically controlled injection systems, such as a pump-nozzle system, valves are used, which are operated by means of a piezoelectric actuator. Determination of the closing time of the valve used to adjust the hydraulic pressure is an important parameter for the hydraulically controlled injection system and it must be detected and controlled in a precise manner.
A method and device for regulating the quantity injected in the case of a fuel injection valve with a piezoelement actuator are known from DE 199 30 309 C2. The fuel injection valve has a control chamber, which is located in a high-pressure receiver and connected to a control valve. Pressures in the control chamber act on a movable nozzle body with a nozzle needle for opening and closing injection holes. The control valve is operated by the piezoelectric actuator to open the injection valve. The voltage at the piezoelectric actuator is detected after initial charging and the start of injection and/or the needle opening time of the injection valve is/are determined from the measured voltage.